Fix HTML string methods to not depend on replace method

test/mjsunit/es6/string-html.js

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Tests taken from:
 // http://mathias.html5.org/tests/javascript/string/
 
 assertEquals('_'.anchor('b'), '<a name="b">_</a>');
 assertEquals('<'.anchor('<'), '<a name="<"><</a>');
 assertEquals('_'.anchor(0x2A), '<a name="42">_</a>');
@@ skipping 174 matching lines @@
     'strike',
     'sub',
     'sup',
   ];
   for (var name of methodNames) {
     calls = 0;
     String.prototype[name].call(obj);
     assertEquals(1, calls);
   }
 })();
+
+
+(function TestDeleteStringRelace() {
+  assertEquals('<a name="n">s</a>', 's'.anchor('n'));
+  assertTrue(delete String.prototype.replace);
+  assertEquals('<a name="n">s</a>', 's'.anchor('n'));
+})();